1. Field of the Invention
This invention relates to a new antibiotic designated herein as BMY-42448 and to its use as an antitumor agent. The invention also relates to production of BMY-42448 by fermentation of a new strain of Micromonospora.
2. Description of the Prior Art
On the basis of the physico-chemical properties of a purified sample of BMY-42448, the structure of the compound has been elucidated except for the absolute stereochemistry.
BMY-42448 is classified by the CRC Handbook of Antibiotic Compounds as a condensed macrolactone. It has the unique structural feature of a 13-membered macrolide in which a spiro-.alpha.-acyltetronic acid moiety constitutes the lactone group. Two other examples of antibiotics possessing this distinctive arrangement in the core of their aglycones have been reported (tetrocarcins; Tomita, F. et al, J. Antibiot., 33, 668, 940, 946 (1980) and kijanimicin; Waitz, J.A. et al. J. Antibiotics, 34, 1101 (1981); Mallams, A.K. et al, J. Am. Chem. Soc., 103, 3938, 3940 (1981)). A third closely related group of antibiotics, but possessing an additional oxygen in the macrolactone ring, is exemplified by chlorothricin; Muntwyler, R. et al., Helv. Chem. Acta, 55, 2071 (1972). All of the above materials differ from BMY-42448 in both sugar sidechains and by substitution on the aglycone portion, thus establishing BMY-42448 as a novel antibiotic.